With these two devices you can use your voice to turn on something as simple as a light or as complex as a 3d printer. I have used both the Belkin and the TP-Link both work well with the Echo.
To remote control the 3d printer I use a Rasberry Pi and Octoprint. As of right now no one currently makes a plug-in to interface Octoprint with the Echo but if you are a skilled programmer I think it would be possible. If you do undertake such a task and are successful be sure to share it with me as I would love nothing more than to tell my printer to "Print another Yoda head!"